Furnace repair gun



Aug. 1967 R. J. DEMAISON 3,333,774

FURNACE REPAIR GUN Filed July 17, 19 64 8 Sheets-Sheet 1 J T INVENTOR.

. R.J. De MAISON '5 BY M Mr ATTORN Y5 Aug. 1, 1967 R. J. DEMAiSQN FURNACE REP-AIR GUN 8 Sheets-Sheet 2 Filed July 17, 1964 INVENTOR. Rd. De MAISON I AM ATTORNgIG Aug. 1, 1967 R. J. DEM/HERON FURNACE REPAIR GUN Filed July 17, 1964 8 Sheets-Sheet 5 'mvrzmozz Rd. De MAISON ORNE Y5 Aug. 1, 1967 Fa. J. DEMAiSON 3,333,774

FURNACE REPAIR GUN Filed July 17, 1964 8 Sheets-Sheet 4 3 I I I J} an g u is Y?) m T INVENTOR.

RJ. D6 MAISON BY ATTORNE Y5 Aug. 1, 1967 R. J. DEMAlSON FURNACE REPAIR GUN 8 Sheets-sheaf 5 Filed July 17, 1964 RJ. De MAISON Liv INVENTOR.

ATTO

Aug. 1, 1967 R. J. DEMAiSON FURNACE REPAIR GUN 8 Sheets-Sheet 6 Filed July 17, 1964 INVENTOR.

R.J. De MAISON 1967 R. J. DEMAISON 3,333,774

FURNACE REPAIR GUN Filed July 17, 1964 8 SheetsSheet '7 INVENTOR. Rd. De MAISON Aug. 1, 1967 R.J. DEMAISON 3,333,774

FURNACE REPAIR GUN 8 Sheets-Sheet 8 Filed July 17, 1964 United States Patent 3,333,774 FURNACE REPAIR GUN Raymond J. Demaison, Bronx, N.Y., assignor to Quigley Company, Inc., a corporation of New York Filed July 17, 1964, Ser. No. 383,416 Claims. (Cl. 239-335) This invention is directed to a furnace repair gun designed to mix a finely divided dry refractory material with water and to discharge the mixture in wet slurry form onto the refractory linings of furnaces for maintenance and repair purposes.

The main problem which has confronted the art in this field has been the inability to keep the materials flowing through the conduits in a positive even flow when variations in air pressures are encountered, even though a separate source of air is being used to supply the unit alone. The controls that are used on the compressor sets are not sensitive enough to produce an even pressure air supply but are arranged to cut-out and cut-in at certain pressures, and it is this variation between the cut-out and cut-in, combined with variations in the controls themselves, that furnish a wide pressure variation in spite of storage tanks on the units. This is especially true where large volumes of air are needed and are being withdrawn constantly during a shooting period. The same situation exists in large plants Where the air is being furnished from a central compressor plant through a complex piping system which supplies the whole plant. Here again it can easily be seen that wide variations in pressure will result, due to the air being used at other locations simultaneously.

It was with this background in mind that the instant invention was conceived to overcome the effects of these wide variations in pressure with their subsequent ill effects on the flow of finely divided dry refractory material from a material containing tank to a mixing dis charge nozzle through a material conduit. Heretofore, the variations in air pressure caused a pulsing in the material flow and quite often reached a point where the material ceased to flow or jammed in the conduit and thus necessitated shutting down the unit.

The primary object of the invention, therefore, is to insure a positive even flow of finely divided dry refractory material through a material conduit to a mixing discharge nozzle regardless of the pressure variations in the air supply to the unit.

Another object is to insure the positive even flow of the dry refractory material at controlled rates by varying the pressures and volumes used to accomplish the feeding and positive even flowing of the material.

Still another object is to provide a unit which may be simply and readily controlled by hand operation of a few valves or may be automated if desired to simplify the controls thereof. In addition, the design is such as to allow the exact duplication of fiow rates when shooting subsequent gun loads without changing valve settings.

Still another object is to have a material containing tank that is to be used for the storage of the finely divided dry refractory material of such design as to insure the even feeding and flowing of the material therefrom into the material conduit for transfer to the mixing discharge nozzle. The material containing tank used for the storage of the dry refractory material has a conical bottom portion inwardly sloped to feed the dry refractory material downwardly and directly into a depending cylindrical throat in which a material flow control is located. The top portion of the tank can be of a standard cylindrical design and of any desired length and diameter tcThold a given amount of material. The material containing tank is equipped with a filling valve at the top ice which in conjunction with the material flow control valve at the bottom make it possible to fill the tank with the dry refractory material and also to aerate and pressurize the material contained in said tank.

The operation of the unit in its simplest form is very compact and fool-proof, necessitating only the operation of a few valves and pressure regulators which once they are properly set do not have to be disturbed regardless of pressure variations. The valves that are used at the top and bottom of the tank may be of any one of a standard shielded type which will not become clogged or inoperative under submission to the finely divided dry refractory particles and which are so designed as to insure the sealing of the filling opening and the material flow control valve opening against the internal air pressure used to aerate and pressurize the material for flow control. The sequence of operations that take place when the unit is put into use is as follows:

The material filling valve is opened first after making sure that the material flow control valve is in closed position and then a suitable amount of the finely divided dry material is loaded into the material containing tank. The tank is designed to hold a specific amount of the finely divided dry material and there is always a given vacant space at the top that is available for pressurizi-ng the material. The material filling valve is then closed tightly and the main air valve, which controls the admission of air into the tank, is opened to full line pressure so as thus to pressurize the unit through the medium of pressure regulators which have been preset to a given pressure to allow air to be fed into a first air jet located above the material fiow control valve and which directs an air stream downwardly through the opening of said valve. The material flow control valve, being initially in a closed position, will cause the air being emitted from said air jet to be fed upwardly through the finely divided dry refractory material in the tank to loosen it up and cause it to become aerated for positive even flow when the unit is in operation. Simultaneously, air is thereby supplied to the space at the top of the dry refractory material contained in the tank to pressurize said material but the space is of such volume that the air being introduced through the first air jet will initially aerate the material contained in said tank and continue to bleed upwards through the material to form the pressurizing means. The same regulator which supplies air to the first air jet will also supply air at the same pressure to a second air jet located below and at right angles to the opening in the material flow control valve and which is arranged to discharge an air stream into the airborne material as it is fed from the material containing tank into the material conduit and mixing discharge nozzle when the unit is in operation. When the material control valve is closed, the second air jet will furnish air to clean out the material conduit and mixing discharge nozzle.

In addition, the air pressure will be fed to the water containing tank to pressurize the water in the tank at main air line pressure. The use of the same air pressure to simultaneously pressurize the dry refractory material in the material containing tank and the two air jets used to insure the movement of said material is predicated on the fact that under normal operating conditions, with the two air jets bleeding air, the pressure being supplied to the top of the dry material remains slightly below that supplied to the air jets. This pressure differential, which is automatically established, will allow the air pressure being used on the air jets to still cause aeration just above the opening of the material flow control valve and thus keep this material in an air-borne state while the air pressure being bled off and applied on top of the dry refractory material will still cause it to be fed downwardly in the tank to the material flow control valve. The result is that it is possible to feed the dry refractory material downwardly towards the opening contained in the material flow control valve where it can be acted on directly by the downwardly directed air stream emanating from the first lair jet to thus make the material completely air-borne and then positively convey the dry refractory material downwardly through the material flow valve opening when the valve is in open position. The stream of air-borne dry refractory material being fed downwardly through the opening of the material flow control valve will then be acted on by the horizontally directed air stream emanating from the second air jet located directly below and at right angles to the opening of the material fiow control valve to thus redirect and continue to convey the dry refractory material into and through the material conduit to the mixing discharge nozzle for mixing therein and discharge therefrom in slurry form.

The action of the air jets contained above and below the material flow control valve is predicated on and controlled by the size of the openings contained therein and the pressure being employed. The opening contained in the first air jet is of such size as to deliver a sufiicient volume of air at a given pressure to convey a given amount of material at a given flow rate downwardly through the material flow control valve opening. The opening contained in the second air jet is of such size as to furnish a sufficient additional volume of air at a given pressure to redirect and convey the material being fed downwardly through the valve opening into and through the material conduit and into and through the mixing discharge nozzle. In a normal gun, the size of the opening contained in the first air jet is slightly smaller than that contained in the second air jet in order to supply the additional air needed to move the material through the material conduit and mixing discharge nozzle in a steady stream without pulsations.

It may be noted that the length and size of the material conduit and the mixing discharge nozzle openings will produce a certain amount of friction head loss and,

in addition, the mixture of the material with water in the mixing discharge nozzle will also produce an additional loss, wherefore the amount of air flowing from the first and second air jets must be sufficient to overcome these losses and cause the slurry to be ejected from the mixing discharge nozzle at a suflicient velocity for spraying. If too high or too low a pressure is employed, a back pressure would be developed which would cause the flow to pulsate and eventually clog up said material conduit and necessitate a shutdown for cleaning out the material conduit and mixing discharge nozzle. If the pressure and volume of air being discharged from the second air jet are too great, it might cause the flow of dry refractory material from the tank to be affected and in extreme cases even stopped. It can thus be seen that the volume of dry material as well as the sizes of the material conduit and mixing discharge nozzle being used, together with the length of said material conduit, are the governing factors involved in sizing the air jet openings and the pressures used to produce the force necessary to move the material therethrough in a steady stream.

It is now evident from the above description that the design of the material containing tank with its material flow control valve and the two air jets for conveying the dry material in an even positive flow form an important part of the system. Inherently, the design of the material containing tank is of importance, as it must allow all of the material contained therein to be fed downwardly at a continuous rate, regardless of variations in air pressure, into the cylindrical throat at the bottom and through the material flow control valve arranged therein. Of equal importance is, first, the necessity of the complete aeration of the material contained in the tank to loosen it up and allow it to more readily become airborne and, secondly, the continuous aeration of the material above the first air jet to insure an even flow of the air-borne dry material through the opening of the material flow control valve. The pressure applied to the top of the material contained in the tank is very nearly the same or less than the pressure applied to the first air jet. The net result is the even continued aeration of the dry material contained above the material flow control valve to utilize the full effect of the air being ejected from said first jet to insure the continual aeration of the dry material and thus provide even feeding of the air-borne material through the material flow control valve. The pressures applied at the two jets and that applied on top of the dry material is such as to insure the continual feeding of the material downwardly and thus allow for the continual aeration and feeding of the dry material to result in its positive feeding. In addition, the pressure applied to the top of the dry material is sufficient to be distributed over the maximum area of the tank when the tank is full and thereby move the heavy mass downwardly in combination with the forces of gravity, and as the mass approaches the bottom of the tank, where the tank sides incline inwardly, the area becomes smaller and the mass becomes smaller but the top air pressure will still apply a suflicient force to insure the positive even feeding of the material from the tank. Thus, it is possible, by varying the air pressures and volumes of air emanating from the two air jets and the application of a given pressure on the top of the material in the tank, to control the volume of the 'dry refractory material being conveyed to the discharge nozzle for mixture with water and the discharge of the mixture in wet slurry form.

The pressures and volumes of air used at the two air jets and the pressure difierential established between the pressure applied on the top of the dry refractory material form the two means of flow control of the dry material that can be readily varied. There is another flow control means which can be varied and that is the size of the two air jet openings which control the volume of air going therethrough but these are not constantly variable, as is the pressure, and must be changed by removing the air jets and substituting similar jets with different size openings.

The above, and other objects, features and advantages of the present invention will be apparent in the following detailed description of illustrative embodiment there of, which is to be read in connection with the accompanying drawings forming a part hereof, and wherein:

FIG. 1 is a diagrammatic representation of the unit showing the component parts, piping, air pressure regulators, variable pressure relief valves, etc. of a imple hand valve operated version using only one pressure regulator to establish the pressure differential;

FIG. 2 is an enlarged detailed section of the arrangement of the air jets, Venturi tubes and material flow control valve used at the bottom of the material containing tank to insure the positive even feeding of the dry material to the material conduit and mixing discharge nozzle;

FIG. 3 is a diagrammatic representation of the unit showing the component parts, piping, air pressure regulators, etc. of a simple hand operated version as shown in FIG. 1, but using two pressure regulators, one of which is employed to establish the pressure differential;

FIG. 4 is a diagrammatic representation of the unit showing the component parts, piping, air pressure regulators, etc. of a simple hand operated version as shown in FIG. 3, but using two pressure regulators, one to establish the pressure for use on the second air jet and to feed air to the second pressure regulator which feeds air to the first air jet and also pressurizes the material contained in the material tank;

FIG. 5 is a diagrammatic representation of the unit shown in FIG. 1 but using only one pressure regulator to establish the pressure differential and designed to be completely automated in operation;

FIG. 6 is a diagrammatic representation of the unit shown in FIG. 3, but using two pressure regulators, one of which is employed to establish the pressure diflferential and designed to be completely automated in operation;

FIG. 7 is a diagrammatic representation of the unit shown in FIG. 4 using two pressure regulators and designed to be completely automated in operation;

FIG. 8 is an enlarged detailed section of the elbowshaped connector; and

FIG. 9 is an enlarged detailed section of a modified form of the elbow-shaped connector.

In the description that follows the same numbers will be used in the interest of brevity for parts of the unit which are identical in their action in the control of the unit.

With reference to FIG. 1, which depicts a simple hand operated version using one pressure regulator, it will be noted that the air and water supply lines are indicated by legend and arrows and are arranged to be connected to permanent supply outlets by means of long flexible conduits in order to make the unit mobile. The material containing tank 10 is equipped with the material filling valve 11 arranged at the top of the upper cylindrical portion 10a and operable from a normally closed position to an open position for filling said tank with dry material 12, care being taken to leave a space 13 on top for pressurizing the material. The tank 10 is also equipped with the material flow control valve 14 suitably arranged in the cylindrical throat 100 depending from the lower conical portion 10b of the tank. The water containing tank 15 is arranged to be filled to a certain level to store a given amount of Water 16 therein and leave a space 17 above for pressurizing the water. The water level in the tank 15 is controlled by the water tank overflow pipe 18 while the actual pressurizing is controlled by the water tank overflow and pressurizing valve 19. The water pipe 20 with the water supply valve 21 contained therein form the means for filling said tank.

The air line 22 is provided with a main air supply valve 23. In order to put the gun into operating condition, it is necessary to open valve 23 and allow air to be fed directly to air pressure regulator 24, which reduces the pressure to a suitable value and supplies air at the reduced pressure to the first air jet 25 through the check valve 26 and simultaneously to the second air jet 27. The check valve 26 is interposed between the jet 25 and the pressure regulator 24 in order to prevent the finely divided dry material getting back into said pressure regulator 24. The variable pressure relief valve 28, arranged at the top of the material containing tank 10, is set to relieve the pressure applied to the top of the material and can therefore be preset to give the desired lower pressure necessary to pressurize the material in the tank. As the air pressure i applied to the first air jet, air will bleed upward through the material in the tank 10 and supply the air to pressurize the material without the use of a direct air line feed. Air is bled from the space 13 at the top of the tank 10 through the pipe 30 equipped with the air bleeder valve 31 for 'depressurizing the tank when the unit is closed down.

The opening of the main air valve 23 also applies the line pressure to pressurize the water tank at full line pressure. The check valve 33 as well as the pressure the water conduit 35 which terminates in the water discharge nozzle 36 leading into the mixing discharge nozzle 37. The water conduit 35 is equipped with the drain valve 38 and with the water flow control valve 39.

The pressurized dry material is fed from the tank 10 through the material flow control valve 14 into the material conduit 40 connected at its terminal end to the mixing discharge nozzle 37. As will later be described, the water from the conduit 35 and the dry material from the conduit 40 are mixed together in a mixing element before the mixture is discharged into the mixing discharge nozzle 37.

The water conduit 35 and the material conduit 40 are both flexible and made of any desired length and diameter, while the mixing discharge nozzle 37 i rigid and has a definite length and diameter according to the volumes and pressures used in the unit and the location to be sprayed.

In putting the unit into operation, assuming the valves are in a normal position (as would be at the end of a run and the gun was put into inoperative position) the following sequence takes place (assuming the following valve are in the position indicated, that is to say, main air valve 23 in closed position, air bleeder valve 31 in open position, water flow control valve 39 in closed position, and water tank overflow and pressurizing valve 19 in open position, and water supply valve 21 in closed position):

(1) Open material filling valve 11.

(2) Close air bleeder valve 31.

(3) Fill tank 10 to give dry material content 12, leaving space 13 at the top.

(4) Close material filling valve 11. v

(5) Open water supply valve 21 and fill water containing tank 15 until water runs out overflow pipe 18, giving a body of water 16 in said tank with a pressurizing space 17 above.

(6) Close water supply valve 21.

(7) Close water tank overflow and pressurizing valve 19.

(8) Open main air supply valve 23 to apply full air line pressure to the water containing tank 15 to pressurize the water 16 therein and to the air pressure regulator 24 which causes air to be discharged through the first air jet 25 to feed air upwardly through the finely divided dry refractory material in the tank 10 for aeration thereof and in addition to pressurize the space 12 above the dry material 12 and which regulator also causes air to be discharged through the second air jet 27 to blow out the material conduit 40 and mixing discharge nozzle 37. The air pressure regulator 24 is set at a predetermined value to deliver the desired volume of dry material from the tank into the material conduit 40 for delivery from the mixing discharge nozzle 37. The dry material is pressurized initially to the same pressure as that applied to the first jet 25 but the variable pressure relief valve 28 will relieve the pressure in the space 13 at the top of the tank 10 and blow off to give the proper differential; under operating conditions, the discharge of the air through the two air jets results in a slightly lower tank pressure. The greater the pressure differential used, the lower the rate of feed of the dry material through the material flow control valve.

(9) The unit is now ready for operation and the material flow control valve 14 is opened to allow the finely divided dry refractory material to be fed downwardly therethrough under the influence of the pressure exerted by the air in the space 13 as well as under the influence of the downwardly directed air stream issuing from the first air jet 25. Thereafter, under the combined influence of the air streams issuing from the second air jet 27 as well as the first air jet 25, the air-borne material is conveyed through the material conduit 40 and the mixing discharge nozzle 37.

(10) Open the water control valve 39 and thereby cause water under pressure to be injected from the water discharge nozzle 36 into the finely divided air-borne dry 7 material passing from the material conduit 40 into the mixing discharge nozzle 37, thereby causing the water and dry material to be mixed into a suitable slurry and discharged in that form from the mixing discharge nozzle.

The unit is now in full operation and may be kept in this state until the entire load of dry material is used up or may be stopped at any time simply by closing the material flow control valve 14 (which stops the flow of dry refractory material) and then closing the water control valve 39, while the air being discharged from the second air jet 27 will clean out the conduit 4% and the mixing discharge nozzle 37, after which the main air supply valve 23 is closed to shut off the unit.

' If the unit is again to be put in operation, when some of the material 12 remains in the tank, the main air supply valve 23 is opened to thus condition the whole unit for operation and the material flow control valve 14 is opened after which the water control valve 39 of the nozzle 37 is opened.

If the refractory material 12 is all used up, the water control valve 39 is closed first to allow the air to clean out the material containing tank, the material fiow control valve, the material conduit and the mixing discharge nozzle, after which the other valves are operated in the following sequence to put the unit out of operation and ready it for reloading.

(l) The material flow control valve 14 is closed.

(2) The main air supply valve 23 is closed to thus remove the air pressure from the water tank 15 and material containing tank 10, and the first air jet 25 and the second air jet 27.

(3) The air bleeder valve 31 is now opened to depressurize the material containing tank and allow it to be reloaded after first closing said valve 31.

(4) The water tank overflow and pressurizing valve 19 is now opened and the air pressure in the water tank relieved.

(5) If the unit is to be put completely out of operation, the water drain valve 38 may be opened and the V tank 15 drained to prevent freezing and the water fiow control valve 39 may also be opened to allow all of the water to be drained from the system. If the units are so arranged that they cannot be completely drained, the air pressure may be used by opening the main air valve 23 to blow all of the water out of the lines.

From the foregoing description of the operation of the unit, it can be seen that it is very simple and foolproof in its operation and readily controllable when it is desired to vary the volumes of the material in slurry form being discharged from the nozzle 37. In addition, it is possible to reproduce the conditions and discharge load after load at the same rate without any difficulty, as the air pressure regulator 24 once set will reproduce the same pressure and pressure differential as long as the as the main air line pressure stays within limits. If the main air line pressure drops, the unit will still operate and deliver material at a reduced rate depending on the air pressure drop and not clog up; and immediately upon resumption of the minimum required pressure required, the unit will perform normally as set up. This fact alone is of importance, bearing in mind that furnances, such as the open hearth and other steel making units (like Kaldo, Linz-Donowitz and oxygen converters) are being used in increasing numbers and at higher heats, which predictably will necessitate constant maintenance to keep their linings in repair and prevent loss of production during relining periods, thus achieving the maximum number of tons of steel production per dollar of lining cost. With the instant unit, this desirable result can be achieved since the unit is always ready for operation and will not plug up or clog and require a complete break down of the unit for repairs and replacements.

The unit disclosed above will operate under normally fluctuating air pressure to give positive flow control with maximum capacity flow at the start with a gradually 8 decreasing flow resulting from the automatic reduction of the top of tank space pressure resulting from the loss of material volume and weight and increase of air volume. Under normal conditions, the unit will handle from 100# to 400'# per minute of dry material with pressure variations of from 20 to per square inch.

With reference to FIG. 2, this is an enlarged detail drawing of the arrangement of the air jets, Venturi tubes and the material flow control valve used at the bottom of the material containing tank to insure the positive feeding of the dry material to the material conduit and mixing discharge nozzle shown in diagrammatic form in FIG. 1. The results described above in connection with FIG. 1 are primarily due to this arrangement which insures even positive feeding and flow of the dry material under wide pressure variations.

Reference is first made to the air jet 25, which is arranged to downwardly direct an air stream under normal operating conditions when the gun is in operation. The discharge opening of the first air jet 25 is slightly smaller in size than that of the second air jet 27 and so designed as to deliver a given volume of air at a given pressure to thereby insure the continuous aeration'and transfer of the dry material downwardly through the throat 10c and open material flow control valve 14 and through the Venturi tube 41. When the valve 14 is in closed position, the air discharged from the first air jet 25 rises upwardly through the mass of dry material to thus aerate same when air is first turned on and loosen up the material; in addition the air initially pressurizes the material with a definite differential being established through the medium of the variable pressure relief valve 28as shown in FIG. 1. There is thus provided a constant force on the top of the mass of dry material in the tank 10 which insures the downward feeding of the material into the material flow control valve when in open position. By varying the pressures at which the relief valve 28 will blow off, various differentials can be obtained.

Reference will now be made to a combination of the action and reaction caused by the first air jet 25 and 'its associated Venturi tube 41. The primary function of the Venturi tube, when the material fiow control valve 14 is open, is to create a back pressure above the tube in the throat 10c to thus cause the air being discharged from the first air jet 25 to continuously aerate the material contained in the throat above and around the air jet 25 and cause the material 'to become air-borne. The airborne material is then fed downwardly under the influence of the downwardly directed air stream from the first air jet 25 through the opening of the material flow control valve 14, and then the Venturi tube 41 takes over and, due to its restriction, causes an increase in the velocity of the air passing ther'ethrough to create a decrease in pressure suction on the intake side of the Venturi tube which will insure the continuous transport of the air-borne material therethrough. It is evident therefore that the Venturi tube 41 serves a dual purpose, one, to cause a restriction therein of the air emanating from the first air jet 25 to first continuously aerate the dry material and cause it to become air-borne and, two, once the material has become air-borne, cause said material to be fed downwardly through the Venturi tube at a slightly greater velocity and also create a decrease in pressure on the intake side thereof.

The next reference will be made to the combination of the second air jet 27 and the two Venturi tubes 41 and 42. In this instance, the Venturi tube 41 serves to help control the air pressure in the material conduit entrance and prevents the reverse fiow ofair up into the Venturi tube 41 while still feeding the air-borne material downwardly therethrough in an even stream. The air emanating from the second air jet 27 enters the material conduit entrance at right angles to the stream of dry material emanating from the Venturi tube 41 and acts to break up said stream of air-borne material as it is expanding and slowing down,

whereby the air-borne material is redirected into the Venturi tube 42 in which the velocity of the air stream is again raised as it is forced therethrough. Here it may be noted that the volumes of air and the pressures used in the air jets 25 and 27 must always be held to within as close limits as possible, with the air jet 25 usually having a slightly lower pressure than air jet 27, in order to insure the positive even flow of the dry material. The volumes of air having been very nearly doubled (the flow of air from two air jets 25 and 27), the material is therefore forced through the Venturi tube 42 at a much greater velocity than that obtained through the Venturi tube 41 even in spite of the fact that the opening of the Venturi tube 42 is slightly larger than that of the Venturi tube 41. The

expansion that takes place on the discharge side of the Venturi tube 42 again acts as a pressure reducing means to help move the dry material out of the material conduit entrance and material conduit and convey the material to the mixing discharge nozzle for mixture with water therein into a slurry of desired viscosity. In this instance, the Venturi tube 42 forms a means for controlling the pressure in the main portion of the material conduit to provide still another means for insuring the positive even flow of the dry refractory material. In this manner, the friction losses encountered in the material conduit 40 and the back pressure resulting from the addition of the water to produce the slurry in the mixing nozzle are overcome by the volume and pressure of the air emanating from the two air jets 25 and 27 and the control of said air by the two Venturi tubes 41 and 42 The combination of the two air jets and the two Venturi tubes with the pressure application on the top of the dry refractory material therefore form a system which can be infinitely varied to vary the volume of material being fed to the mixing discharge nozzle. In addition, the use of the air jets on which the pressure can be varied also forms an additional means for volume control without changing the size of the jet openings. In addition, the size of the openings in the two jets 25 and 27 can be varied and normally the size of the opening in air jet 25 is slightly smaller than the opening in the air jet 27. The net result is to insure the flow of the finely divided dry material under positive control and which flow is practically insensitive to pressure variations in the air line pressure unless they drop to such a low value that the necessary force is not sutficient to overcome the resistance it meets.

FIG. 3 represents a simple hand operated version, using two pressure regulators; otherwise it is the same as that in FIG. 1. An added pressure regulator 43 is inserted in the air line 32a delivering air to the top of the material in the tank at a predetermined pressure for pressurizing the material and thus insuring the downward feeding of the material through the material flow control valve 14 in a steady even flow where it is acted upon by the downwardly directed air stream emanating from the first air jet 25. The insertion of the pressure regulator in this separate air supply line allows greater and more constantly .maintained pressure differentials than can be secured in FIG. 1. There will be no change in the operation of the unit from that described in FIG. 1 and FIG. 2 with the exception that the pressure regulator 43 will be set to provide the proper pressure dilferential before starting. The net result attained by this addition is to allow a greater latitude in flow control than is possible by the application of a given fixed pressure as happens in the use of a variable pressure relief valve alone. Such a relief valve will naturally, under the influence of the air pressure being drawn from the first air jet, remain constant only within certain limits, merely preventing the pressure from reaching too high a value under a given set pressure. It

might be stated here that in this second version another check valve 44 is placed in the air line 32 to protect the 'pressure regulator 43. The unit disclosed above will operate under normally fluctuating air pressure to give positive flow control with a positive delivery capacity due to the use of two separate and distinct air supplies in the material tank supplied with two separate and distinct pressures.

FIG. 4 represents a simple hand operated version, using two pressure regulators; differently located in the air lines, otherwise it is the same as that shown in FIG. 3. The normal pressure regulator 24 is used to supply the air to the second air jet 27 but in addition is used to supply the second pressure regulator 43 located in the branch air line 22b. In this manner, there is established a definite pressure differential between the air pressures being supplied to the first air jet 25 and the second air jet 27. The air being supplied to pressurize the top of the material contained in the tank 10 is further stabilized and controlled to create a definite pressure differential by the use of the check valve 44 and variable pressure relief valve 28. Hence, the pressure applied to the top of the material can be held to closer limits and in addition a certain pressure differential is established and maintained between the two air pressures used at the two air jets to thus insure an even flow of material at a given rate through the material conduit to the mixing discharge nozzle. The insertion of the pressure regulator 43 on the discharge side of the pressure regulator 24 provides even still greater and more constantly maintained pressure differentials than can be secured in FIG. 3. There will be no change in operation of the unit from that described in FIG. 1 and FIG. 3.

FIG. 5 depicts an automated version of the unit shown in FIG. 1 but it will be noted that the layout of the equipment, piping and control valves, etc. is exactly the same as that shown in FIG. 1. The entire unit is operable by the manipulation of two two-position air control valves 46 and 47 which in turn operate and control the other valves by means of air actuating units. Recourse will be made to the use of the same numbers for similar valves (air actuated) used to accomplish the same control functions as originally described in FIG. 1.

In putting the unit into operation, it will be assumed that the valves will be positioned as would normally occur on a shutdown and the following sequence will take place (assuming water drain valve 38 in closed position and air control valve 46 in off position as indicated at 48 and air control valve 47 in off position as indicated at 50 and water flow control valve 39 and water supply valve 21 are in closed position) (1) Open main air shutoif valve 52 to thus pressurize the entire unit with line air pressure.

(2) With air control valve 46 in off position as indicated at 48, the following valves will be in the following positions:

(a) Main air supply valve 23 in a closed position,

(b) Material tank air bleeder valve 31 in open position,

(c) Water feed valve 53 in closed position,

(d) Water tank overflow and pressurizing valve 19 in open position.

(3) With air control valve 47 in off position as indicated at 50 the following valves will be in the following positions:

(a) Material flow control valve 14 in a closed position. (4) The water supply valve 21 on water conduit 20 is hand operated to open position to allow water to flow into water containing tank and fill same to overflow conduit 18 level to produce a definite water level, creating the space 17 above the water in the tank for pressurizing after which valve 21 is closed.

(5) The material filling valve 11 is opened by hand and the material containing tank 10 filled to create the mass 12 and the space 13 above for pressurizing and aeration.

(6) The material filling valve 11 is then closed by hand and the material containing tank is ready for spraying.

(7) The air control valve 46 is then hand operated to on-position as indicated by 49 to actuate the following valves to the position indicated:

(a) Main air supply valve 23 to an open position to put air on entire unit for operation, including main air line pressure on the water containing tank ready for pressurization and to the pressure regulator 24 to thus cause air to be discharged through the first air jet 25 to feed air upwardly through the finely divided dry refractory material in the tank for aeration thereof and in addition to pressurize the space 13 above the dry refractory material 12, and also air issuing from the second air jet 27 will blow out the material conduit 40 and mixing discharge nozzle 37. The air pressure regulator 24 is set at a predetermined pressure to deliver a given volume of material to the mixing discharge nozzle. The check valve 26 is added to protect the air pressure regulator against a back feed of dry refractory material,

(b) 'Ma-terial tank air bleeder valve '31 to closed position to thus allow material containing tank to be pressurized,

(c) Water tank overflow and pressurizing valve 19 to a closed position to allow the water containing tank to be pressurized,

(d) Water feed valve 53 to an open position to feed water to the mixing discharge nozzle.

(8) The air control valve 47 is then hand operated to on-position as indicated by 51 to actuate the following valves to the position indicated:

(a) Material flow control valve 14 to an open position to thus cause the finely divided dry refractory material to be fed downwardly through the opening of the material flow control valve in an even stream and then outwardly through the material conduit and mixing discharge nozzle.

(9) Open water control valve 39 by hand to cause a sufficient amount of water to be discharged through water discharge nozzle 36 to cause the dry material to be mixed into a slurry of proper viscosity in the mixing discharge nozzle 37.

The unit is now in full operation and capable of discharging from the mixing discharge nozzle 24 in wet slurry form a proper mixture of the dry material with water. The air pressures applied to the top of the dry material and through the two jets will control the volume of material being discharged. The u-nit operates very smoothly with an even discharge and no pulsing as long as the main air line pressure does not fall too far below the pressures being used and controlled by the air pressure regulators. The unit may be used to shoot the entire load or may be shut off at any point during the shooting; and as long as there is water and refractory material contained in the tanks the unit will continue to discharge the slurry when again put in operating position.

In shutting off the unit, the reverse order of operation is indicated as follows (after shutting off Water flow control valve 39). i

' (1) The air control valve 47 is hand operated to an off position as indicated at 50 to actuate the following valves:

(21) Material flow control valve 14 to a closed position ready to further use the remaining material and empty the load or be ready for the next load of refractory material.

(2) The air control valve 46 is then hand operated to an off-position as indicated at 48 to actuate the following valves to the position indicated:

(a) Main air supply valve 23 to a closed position to cut air off the entire unit and make it inoperative,

(b) Material tank air bleeder valve 31 to an open position to bleed oif any air pressure that may have remained in the material tank 11 before opening material filling valve 47 for refilling,

(c) Water tank overflow and pressurizing valve 19 to an open position to depressurize the water containing tank,

(d) Water feed valve 53 to a closed position to stop the feed of water to the mixing discharge nozzle.

The above outline of steps indicates the operation of the unit and discloses an automated system wherein the two air control valves 46 and 47 are operated by hand although they themselves could be operated from a single hand control unit, either mechanically or hydraulically. The entire unit could be magnetically controlled, or by the use of air, oil or water as desired to simplify the unit and reduce the piping. Air was chosen in the present instance as it is always available at steel mills.

The outstanding advantages of the instant invention are its simplicity of operation and control and its ability to duplicate the volumes and mixes consistently without any difficulty. In addition, it allows for pressure variations in the main air line while still being able to use the unit without pulsing or clogging. In other words, it represents a new concept in positive flow control and may therefore be used in many other applications where pressure variations cause pulsing and clogging. There is one fact that may be mentioned and that is the pressure differential used should not be too great, as the greater the differential established the harder it is to move the mass in the tank evenly. Also it may be noted that a unit designed to deliver a certain amount of material per minute and having certain size hoses and nozzles cannot be used or forced to supply over a given amount simply by raising the air pressures used.

FIG. 6 depicts an automated version of the unit shown in FIG. 3 but it will be noted that the layout of equipment, piping and control valves etc. is exactly the same as that shown in FIG. 3. The entire unit is again operable by the manipulation of two two-position air control valves 46 and 47 which in turn operate and control the other valves by means of .air actuating units. The sequence of operation is the same as that shown in FIG. 5 with the exception that the control of the water tank overflow and pressurizing valve was removed from air control valve 46 and added to valve 47 to thus allow the water to be controlled and pressurized at the same time as the material flow control valve 14 is actuated. Otherwise the controls and the sequence of operation of said controls is identical. The sole reason for showing this change was to allow the versatility of the control of the unit to be demonstrated by variations thereof.

FIG. 7 depicts an automated version of the unit shown in FIG. 4 :but it will be noted that the layout of equipment,. piping and control valves is exactly the same as that shown in FIG. 4. The entire unit is again operable by the manipulation of two two-position air control valves 46 and 47 which in turn operate and control the other valves by means of air actuating units. It might be stated here that these canbe further controlled and actuated to make the entire unit operable by the manipulation of a single handle on a single valve. The sequence of operation is the same as that shown in FIG. 6 to thus make the unit extremely flexible in operation.

It may be stated here that the variable relief valve may be dispensed with on FIGS. 6 and 7 and a standard relief valve substituted therefor if desired, in which case it will simply act to relieve the pressure in the tank if it gets too high.

Reference is now made to FIG. 8 which is an en larged detail section of the mixing element shown only diagrammatically in FIGS. 1, 3, 4, 5, 6 and 7. The main part of the mixing element is the metal elbow-shaped connector 54 designed for connection at one end to the material conduit 40 and at its other end to the mixing discharge nozzle 37, said connector having mounted therein a water discharge nozzle 36 designed for connection at one end to the water conduit 35 with the water flo-w control valve 39 arranged thereon. The arrangement depicted shows a centrally located water discharge nozzle 36 containing a suitable plurality of outwardly directed holes 55 to direct the water into the air-borne refractory material to-thus cause a slurry of a suitable viscosity to be formed in the mixing discharge nozzle 37. The water discharge nozzle 36 is connected to the end of the flexible water conduit 35 and with the controlvalve 13 39 forms the means for feeding and controlling the supply of water to the nozzle 37. It will be noted that the nozzle design is very simple and eflicient and the parts thereof are readiy replaceable.

FIG. 9 represents a modified form of the elbow-shaped connector. In this instance, the water discharge nozzle 36 is connected at its discharge end to a mixing element 57 having a central passage 56 leading from the water discharge nozzle into the mixing discharge nozzle 37, said mixing element also having a plurality of arcuate openings 58 arranged concentrically around said central water passage 56 and leading from the elbow-shaped connector into the mixing discharge nozzle. The inner and outer walls of said arcuate openings are cone shaped and arranged to converge in the direction of flow whereby the material as it enters the mixing discharge nozzle from the material conduit is directed into and across the path of the water as it enters said nozzle from the water conduit.

It is evident that there are actually three separate and distinct versions of the instant invention disclosed herein, each one capable of accomplishing certain end results as will be hereinafter spelled out.

(1) A design which will give positive flow control with a given maximum flow capacity at the start with said fiow capacity gradually decreasing automatically clue to the reduction of pressure being applied on the top of the material due to loss of material volume (also weight) and or the increase of the volume of air contained above said material.

(2) A design which will give positive flow control with a positive given capacity throughout the cycle due to the control of the pressure being applied on the top of the material remaining constant due to the two air feeds to the material tank, one at the top and the other at the bottom with different pressures being applied.

(3) A design which will give positive flow control with a constant maximum positive capacity throughout the cycle based on a more accurate control of the pressures being applied on the top of the material and that to the first air jet.

It must be remembered that the air being discharged downwardly from the first air jet is used to:

1st. Aerate the material in the tank both initially and continuously when the unit is in operation.

2nd. Positively feed the aerated material downwardly through the material flow control valve in open position.

3rd. Supply the initial amount of air necessary to move the air-borne material through the material conduit into and through the mixing discharge nozzle.

What is claimed is:

1. A furnace repair gun for spraying a wet slurry of dry refractory material mixed with water as a protective coating upon the refractory linings of high temperature furnaces comprising, in combination,

(a) a mixing discharge nozzle,

(b) a material containing tank,

(c) a material conduit leading from said tank to the mixing discharge nozzle,

(d) a water conduit leading from a suitable pressurized water supply to the mixing discharge nozzle and having a water flow control valve,

(e) a material flow control valve located at the lower end of the material containing tank and adjustable to an on and off position only for feeding material from said tank to the material conduit,

(f) a first air pressure pipe leading to the top of the material containing tank for supplying superatmospheric pressure downwardly upon the top of the material in the tank,

(g) a second air pressure pipe equipped with a first air jet located within the bottom of the material containing tank and arranged in a permanent fixed position above the material fiow control valve,

(1) said jet being operative, when the material flow control valve is in ofl position, to direct air under superatmospheric pressure into the material contained in the tank in order to preliminarily aerate said material and render it sufiiciently fluent for easy fiow,

(2) and said jet being operative, when the material flow control valve is in on position, to direct air under superatmospheric pressure downwardly through the opening of said valve into the open receiving end of the material conduit and thus aid in feeding the material from the tank into the conduit while continuing to aerate the flowing material,

(h) a third air pressure pipe equipped with a second air jet located within the material conduit below the material flow control valve and arranged in a permanent fixed position to discharge air under superatmospheric pressure into the air borne material as it is fed from the material containing tank into the conduit and thus cause further aeration of the flowing material while transporting it through the material conduit and through the mixing discharge nozzle,

(i) and an air pressure control system connected to the three air pressure pipes and comprising,

(1) a single main air flow control valve adjustable to an on and off position only,

(2) and pressureregulating means to constantly maintain preset fixed air pressures in all three air pressure pipes when the main air control valve is adjusted to on position,

whereby, when the material flow control valve is adjusted to its ofi position, superatmospheric air will be supplied at the preset fixed pressures to the top and bottom, respectively, of the material containing tank for the desired preliminary aeration of the material therein as well as to the second air jet to set up air flow through the conduit and mixing discharge nozzle, and whereby, when the material flow control valve is adjusted to its on position, superatmospheric air will be supplied at the preset fixed pressures not only to the top of the material containing tank but also to the first and second air jets to cause the aerated material to be fed positively and at a substantially constant rate from said tank into the material conduit and thence through the material conduit and the mixing discharge nozzle.

2. A furnace repair gun according to claim 1, including a Venturi tube located below the material flow control valve and through which the air-borne material is discharged from the material containing tank into the material conduit under the propelling influence of the first jet when said valve is open.

3. A furnace repair gun according to claim 1, including a Venturi tube located in the material conduit beyond the second air jet for controlling the flow of the air-borne material through said conduit under the propelling influence of said second jet.

4. A furnace repair gun according to claim 1, including a first Venturi tube located below the material flow control valve and through which the air-borne material is discharged from the material tank into the material conduit under the propelling influence of said first jet when said valve is open, and a second Venturi tube located in the material conduit beyond the second air jet for controlling the fiow of the air-borne material through said conduit under the propelling influence of both jets.

5. A furnace repair gun according to claim 1, wherein the first and second air jets are formed with discharge openings of different sizes so as thus to supply a given volume of air from each air jet at their respective preset fixed pressures.

6. A furnace repair gun according to claim 1, wherein the air pressure regulating means to constantly maintain preset fixed air pressures in all three air pressure pipes include a single pressure regulator which controls the 15 supply of air pressure to both the first air jet and the second air jet.

7. A furnace repair gun according to claim 1, wherein the pressure regulating means to constantly maintain preset fixed air pressures in all three air pressure pipes include two pressure regulators, one directly controlling the air pressure supplied to the second air jet and a second regulator directly controlling the air pressures supplied to the top of the material in the material containing tank and to the first air jet.

8. A furnace repair gun according to claim 7, wherein the two pressure regulators are connected in series such that the first regulator supplies a preset fixed air pressure to the second regulator.

9. A furnace repair gun comprising, in combination, a dry refractory material containing tank, a mixing discharge nozzle, means for air-pressurizing the tank, a water conduit leading to the mixing discharge nozzle and equipped with a water flow control valve to control the volume of water discharged into the nozzle, a material conduit leading from the material containing tank to the mixing discharge nozzle, a material flow control valve for feeding the air-borne dry material from the material containing tank to the material conduit, an air pressure pipe equipped with a first air jet located above the material flow control valve to direct an air stream under super-atmospheric pressure downwardly through the opening of said control valve when the latter is open to aid in propelling the air-borne material therethrough, means for constantly maintaining the air discharged from the first jet at a preset fixed pressure to cause the airborne material passing through the material control valve to be discharged therefrom at a continuously controlled rate, a further air pressure pipe equipped with a second air jet located below the material flow control valve and arranged to discharge an air stream under super-atmospheric pressure into the air-borne material as it is fed from the 'material containing tank into the material conduit, and means for constantly maintaining the air discharged from the second air jet at a preset fixed pressure which is slightly higher than'the preset fixed pressure of the first air jet to cause the air-borne material to be transported through the conduit to the mixing discharge nozzle at a continuously controlled rate for intimate and thorough mixing with water in said nozzle to produce a sprayable wet slurry, the preset fixed air trolled as to insure a continuous even flow of the airborne material from the material containing tank to the mixing discharge nozzle as well as a continuous even flow of the wet slurry through and from the mixing discharge nozzle.

10. A furnace repair gun according to claim 9, Wherein the means for pressurizing the material containing tank are regulated to supply an air pressure above the material in the tank which is no greater than the air pressure applied to the first air jet.

References Cited UNITED STATES PATENTS EVERETT W. KIRBY, Primary Examiner.

pressures for the two air jets being so regulated and con 

9. A FURNANCE REPAIR GUN COMPRISING, IN COMBINATION, A DRY REFRACTORY MATERIAL CONTAINING TANK, A MIXING DISCHARGE NOZZLE, MEANS FOR AIR-PRESSURIZING THE TANK, A WATER CONDUIT LEADING TO THE MIXING DISCHARGE NOZZLE AND EQUIPPED WITH A WATER FLOW CONTROL VALVE TO CONTROL THE VOLUME OF WATER DISCHARGED INTO THE NOZZLE, A MATERIAL CONDUIT LEADING FROM THE MATERIAL CONTAINING TANK TO THE MIXING DISCHARGE NOZZLE, A MATERIAL FLOW CONTROL VALVE FOR FEEDING THE AIR-BORNE DRY MATERIAL FROM THE MATERIAL CONTAINING TANK TO THE MATERIAL CONDUIT, AN AIR PRESSURE PIPE EQUIPPED WITH A FIRST AIR JET LOCATED ABOVE THE MATERIAL FLOW CONTROL VALVE TO DIRECT AN AIR STREAM UNDER SUPER-ATMOSPHERIC PRESSURE DOWNWARDLY THROUGH THE OPENING OF SAID CONTROL VALVE WHEN THE LATTER IS OPEN TO AID IN PROPELLING THE AIR-BORNE MATERIAL THERETHROUGH, MEANS FOR CONSTANTLY MAINTAINING THE AIR DISCHARGED FROM THE FIRST JET AT A PRESET FIXED PRESSURE TO CAUSE THE AIRBORNE MATERIAL PASSING THROUGH THE MATERIAL CONTROL VALVE TO BE DISCHARGED THEREFROM AT A CONTINUOUSLY CONTROLLED RATE, A FURTHER AIR PRESSURE PIPE EQUIPPED WITH A SECOND AIR JET LOCATED BELOW THE MATERIAL FLOW CONTROL VALVE AND ARRANGED TO DISCHARGE AN AIR STREAM UNDER SUPER-ATMOSPHERIC PRESSURE INTO THE AIR-BORNE MATERIAL AS IT IS FED FROM THE MATERIAL CONTAINING TANK INTO THE MATERIAL CONDUIT, AND MEANS FOR CONSTANTLY MAINTAINING THE AIR DISCHARGED FROM THE SECOND AIR JET AT A PRESET FIXED PRESSURE WHICH IS SLIGHTLY HIGHER THAN THE PRESET FIXED PRESSURE OF THE FIRST AIR JET TO CAUSE THE AIR-BORNE MATERIAL TO BE TRANSPORTED THROUGH THE CONDUIT TO THE MIXING DISCHARGE NOZZLE AT A CONTINUOUSLY CONTROLLED RATE FOR INTIMATE AND THOROUGH MIXING WITH WATER IN SAID NOZZLE TO PRODUCE A SPRAYABLE WET SLURRY, THE PRESET FIXED AIR PRESSURES FOR THE TWO AIR JETS BEING SO REGULATED AND CONTROLLED AS TO INSURE A CONTINUOUS EVEN FLOW OF THE AIRBORNE MATERIAL FROM THE MATERIAL CONTAINING TANK TO THE MIXING DISCHARGE NOZZLE AS WELL AS A CONTINUOUS EVEN FLOW OF THE WET SLURRY THROUGH AND FROM THE MIXING DISCHARGE NOZZLE. 